1. Field of the Invention
The present invention relates generally to the field of molecular biology. More specifically, the invention relates to methods and compositions for increasing the efficiency of cell transformation.
2. Description of the Related Art
Methods for stably integrating exogenous DNA into a eukaryotic cellular genome typically rely on the presence of one or more breaks in the chromosome as sites for integration. Agrobacterium tumefaciens has been used as a transformation agent due to its natural ability to transfer a fragment of its genome known as the T-DNA into a host plant cell's genome. Other members of the Rhizobiaceae, besides Agrobacterium, have also been shown to be capable of transferring T-DNA to host cell genomes (e.g. Broothaerts et al., 2006), and T-DNA transfer to non-plant cells has also been noted (e.g. Bundock et al., 1995). This T-DNA traverses through the cell cytoplasm and into the nucleus as a nucleo-protein complex, interacting with several host proteins along the way, and finally is integrated into the host genome at random sites via double strand breaks (DSBs) in the host DNA (Anand and Mysore, 2005; Gelvin, 2003; Tzfira and Citovsky, 2006).
The mechanism utilized by A. tumefaciens and related species to transfer T-DNA into plant cells, and other cells thus allows introduction of engineered DNA, for instance comprising a transgene of interest, into cells. Agrobacterium sp., including A. tumefaciens, are also known as soil borne phytopathogenic bacteria that cause crown gall disease in plants.